Transmission of intelligent information via light traveling along glass fibers is on the threshold of commercial reality. In earlier investigations of appropriate systems and glass fiber structures the bulk of the development activity has involved single fibers. However, it is clear that commercial communication systems will employ multiple fibers bound together in some fashion to form a multifiber cable. A part of the recent activity in optical systems has focused on manufacturing methods, structures, and uses for multifiber cable.
There are several potential uses for a multifiber cable in which different fibers within the cable have different transit times for a given cable length. A common pulse applied to the fiber bundle at one end of the cable will arrive at the other end in a series of pulses separated by the difference in transit times. This kind of fiber bundle has been called an "organ array" and is described in U.S. Pat. No. 3,892,468 issued July 1, 1975 to M. A. Duguay and assigned to Bell Telephone Laboratories, Incorporated. Potential uses for organ arrays appear in U.S. Pat. No. 3,838,278 issued Sept. 24, 1974 also to M. A. Duguay, describing an optical switching network, and U.S. Pat. No. 3,849,604 issued Nov. 19, 1974 to E. Benes and M. A. Duguay, describing a time slot interchanger for a time division multiplexing system. Fiber bundles of this type can be used for more basic functions. Moderate lengths are equivalent to multiple tap variable delay lines. They can also be used as pulse generators or for time division multiplexing by combining the outputs, or as scanners with the spatial disposition of the output ends in the output plane defining the raster. The different fiber lengths can be employed to compensate for frequency dispersion when different fibers in the array are used to transmit different frequency bands. There are undoubtedly a variety of other uses for such fiber arrays.